The electrical conductivity of the mantle beneath Europe derived fromC-responses from 3 to 720 hr

The C-response, which connects the magnetic vertical component and the horizontal gradient of the horizontal components of electromagnetic fluctuations, forms the basis for estimating the conductivity–depth profile of the Earth. This paper describes new estimates of the C-response obtained from observatory hourly mean values. The Z:-method is applied, which means that the vertical component is used locally whereas the horizontal components are used globally by expansion into terms of spherical harmonics. A special effort is made to obtain unbiased estimates of C.